plm: Linear Models for Panel Data

A set of estimators and tests for panel data
econometrics, as described in Baltagi (2013) Econometric Analysis of Panel Data, ISBN-13:978-1-118-67232-7,
Hsiao (2014) Analysis of Panel Data <doi:10.1017/CBO9781139839327> and
Croissant and Millo (2018), Panel Data Econometrics with R, ISBN:978-1-118-94918-4.